Process of impregnating fabric



Patented May 7, 1929.

UNITED STATES PATENT OFFICE.

JQHIT ALLEN HEANY, OF NEW HAVEN, CONNECTICUT, ASSIGNOR TO WORLD BESTOSCORPORATION, OF PATERSON, NEW JERSEY, A. COBPORATION OF DELAWARE.

PRO (JESS OF IMIREGNA'IING FABRIC.

No Drawing.

This invention relates to a process of impregnating fabrics with awater-proofing, strengthening and insulat ng material. Moreparticularly,the inventlon relates to a process of impregnating fabrics braided orWoven from yarns formed of mineral substance such as asbestos and usablein connection with brake linings and clutch surfaces where strongresistance to heat and frictional wear is essential.

In the methods heretofore employed 1n the impregnation of fabrics, ithas been usual to apply the impregnating fluid or substance after thefinal fabrication of the material, subjecting the fabric to an immersionor saturation in the impregnating fluid and subsequently through theapplication of heat, diffusing the impregnator into the fabric. lhisprocess has in many ways been unsatisfactory particularly in that the1mpregnating fluid fails to penetrate thoroughly to the interior of thefabr c, especially where the material entering into the yarn structureis of non-fibrous nature, as, for example, yarn formed of pulpy substance held together by an adhesive or outer sheath. Consequently,fabrics subjected to these prior processes have received impregnationonly in the exterior layer of the substance and in use when the exteriorlayer is worn ofi, the unimpregnated interior is eX- posed which lacksthe proper Water-proofing and insulating characteristics of the exteriorlayer and the fabric thus becomes deficient in the purposes for whichthe material 1s used.

It is an object of the present invention, therefore, to utilize aprocess for impregnating fabrics by which all of the fabric from theexterior to the interior shall be thoroughly impregnated with-asubstance designed to water-proof or insulate the same. Anotherimportantobject of the invention isjthe provision of a process in which it ispossible to disseminate the impregnator thoroughly through the fabricmaterial without hindering the various processes incident to themanufacture of the final fabric such as the formation of a material intoyarn, and the subsequent making of the yarn into the final product.Another important object contemplated is the simplification of a meansby which the 1mpregnating substance is added to the body Applicationfiled February 6, 1924. Serial No. 691,010.

material of the fabric. An object also is the utilization of a processwhich is applicable to material either of a fibrous nature such ascellulose or a material which is thoroughly comminuted or ground so asto have very little if any fibrous structure and which, therefore, isrelatively impervious to the action of liquids such as an impregnatingfluid.

Additional objects are involved in the em ployment of a process which isapplicable with equal facility to fabrics manufactured from mineralsubstances such as asbestos and fabrics manufactured from vegetable orother material; in the provision of suitable apparatus for carrying outthe many steps of the process and in various features rela tive to thedetails of the process which will become apparent on consideration ofthe following detailed description of the invention.

Broadly stated, the invention consists in a process involving theapplication of an impregnating substance in the form of a powder to theelementary material going into the manufacture of the yarn by a thoroughmixing of the impregnator with the yarn material and subsequently to theformation of a yarn and the manufacturing of the fabric, in theapplication of a solvent accompanied by the application of heat toloosen the impregnator and diffuse it throughout the fibres andinterstices, and open spaces throughout the fabric. A feature of theinvention is the thorough dissemination of the impregnating substance bymixing or other means through the basic material of the fabric While inits elementary crude form so that the impregnating substance is presentthroughout the whole fabric structure when the same is finally fashionedinto shape as a finished product.

The term fabric as employed in the present specification is intended tocover a manufactured product formed by the combination of variouselementary materials. The fabric may be formed either from yarns whichare of themselves made from substances more elementary or the fabric maybe formed merely by the assembly of elementary substances which are heldtogether by some binding substance, causing a cohesion of the compositeparticles of the materials of the fabric. The term fabric is alsointended to include a product as a yarn which may be employed in furtherprocesses such as weaving. The description, however, will be largelyconfined to the, application of the impregnating substance to a? fabriccomposed of material which is manipulated in pulp and formed into yarnand subse quently braided or woven into a fabric, such, for example, asfabrics manufactured from asbestos.

In carrying out the process as applied to asbestos fibre, theimpregnator in the form of a dry powder normally insoluble in water ismixed with the fibrous abestos in a beater machine. The impregnator mayconsist of a natural asphaltum, such as gilsonite, or substances havingsimilar characteristics.

The beater employed in the mixing of the impregnator and pulp may besimilar in its essential features to that described in my copendingapplication Serial No. 692,947. filed Feb. 15, 1924, Patent No.1,642,495, and consists essentially in a vat in which the material isconstantly moved beneath a rotating wheel having radial blades adaptedto mm and distribute the pulp. The beater includes also pressure guider'olls through which the stream of pulp material is passed. After thebeating process in which the gilsonite, for example, is thoroughly mixedwith the pulp, the same is passed to a paper machine having the generalcharacteristics described in my co-pending application, SerialNo. 654,-117, filed July 27, 1923, Pat. No. 1,681,234 in which the pulp is mixedwith a binder and deposited upon traveling belts and subjected to aseries of compressions and heating operations, being finally formed intopaper sheets and wound into rolls.

The paper=rolls are then sliced and fabricated into yarns in accordancewith the Various steps indicated and claimed in my copendingapplications, Serial No. 654,118, filed July 27, 1928, Patent No.1,585,622, Serial No. 684,325, filed January 4, 1924, Patent No.1,585,614 and Serial No. 685,300,

filed January 10, 1924, Patent No. 1,585,613.

wherein the paper strip containing the powdered gilsonite is moulded,wrapped or twisted either on itself or with a reinforcing core to 'forma strand and subsequently where it is desirable, twisted or wrapped withone or more reinforcing filaments.

The yarns as completed according to the above indicated processes arethen woven or fabricated by an approved means into a brake lining,friction belt orany other desired product. The material is now incondition for the various steps of the process necessary to make thegilsonite, present in the material, effective as a water-proofingmaterial, frictioning agent, or as a toughening or insulating substance.In accordance with the process, the fabric is passed through a solventbath such as a solution of carbon tetrachloride, benzine or benzol inorder to partially or completely dissolve the asphaltum present in thefabric and make it more susceptible to the action of heat. Immediatelyafter subjection to the solvent, the fabric is passed into a heatingoven which is of the type well known in the art consisting in atower-shaped oven having a plurality of rollers at the top and bottomover which the fabric is slowly and continuously moved up and down inthe oven until the gilsonite is thoroughly diffused into all theopenings and interstices of the fabricfand then dried Within the fabric.A passage interval of two or three hours and an oven temperature ofabout 300 Fahrenheit is ordinarily advantageous, where gilsonite is theimpregnator, to accomplish the results desired. After emergence from theoven, the fabric is passed throughpressure rolls to compact the materialand bring it to size.

As a result of the impregnation, the fabric has improved properties, thegilsonite by filling up the spaces and openings of the fabric causingthe same to become relatively stiffer and imparting completewater-proofing and insulating characteristics. The fabric is now readyfor immediate application to the uses for which it is intended. Nherethis use is that of a brake lining, it is apparent that the substance isimpervious to moisture; that it'will prevent the passage of electriccurrent; and that it will have appreciably higher resistance todisintegration from wear and friction induced by contact withexterior-surfaces, as in brake mechanism.

As previously pointed out, the fabric is entirely completed and readyfor applica tion to the uses for which it is designed before it issubjected to the action of a solvent and the heating processes, since aprior treatment would make the yarn too stiff for easy working. Thisrequirement is in fact advantageous as the dissolving and heating stepsmay both be carried out continuously and as a fabric is ordinarily acontinuous structure, the same may be passed through the solvent vat andheating oven in a continuous movement. However, it is within the boundsof the invention to pass the yarn through the dissolving and heatingprocesses prior to fabrication of the finished product where suchfabrication does not involve serious manufacturing difiiculties.

It should be noted that the invention is not limited to the employmentof an asphaltum as gilsonite as an impregnator as it has been found thatnot only materials derived from hydrocarbons, but also dried vegetableoils such as linseed, cotton seed and Chinawood oils and similarsubstances may be used as well as the mineral oils. In addition, whileordinarily advantageous in the carry 'to actuate or to liquefy thegilsonite or render it. fluid and'cause proper diffusion of the samethrough the fabric but this action is slower and possibly moreinefficient than where the solvent is employed.

Various other modifications of the process will be apparent to thoseskilled in the art to which the invention relates, involving the use ofequivalents having similar properties and it is desired therefore tocover the invention broadly as well as specifically as indicated by theclaims hereto appended.

Having thus'described my invention, what I desire to secure by LettersPatent of the United States and claim is:

l. A process of impregnating manufactured fabrics formed of yarnscontaining,

pulpy stock which consists in mixing an 11npregnator in the form ofpowder with the yarn pulp prior to the manufacturing process, subjectingthe fabric to the action of a solvent to dissolve the impregnator, and

' finally subjecting the fabric to a high temperature to difiuse theimpregnator through the fabric.

52. A process of .impregnating fabrics manufactured from yarns formed offibrous stock which consists in mixing the impregnator in the form of apowder with the stock prior to the makin of the yarn, and subsequenttothe manu acture of the fabric dissolving the impregnator, and finallysubjecting it to the action of heat to diffuse the impregnator th oughthe fabric.

3. A process of impregnating fabrics manufactured from yarns whichconsists in mixing the impregnator with the stock prior to the making ofthe yarn, and subsequent to the manufacture of the fabric subjecting thefabric to the action of heat to diffuse the impregnator through thefabric.

4. A process of impregnating fabrics which consists in mixing with theelementary fabric material, prior to fabrication, an impregnatingsubstance, in the form of a powder insoluble inwater, and aftermanufacture of the fabric subjecting the same to disseminated anddiffused through the fabric.

5. A process of impregnating a yarn formed of separate elementarymaterials held together by a binding agent which consists in mixing thematerials prior to fabrication into yarn with an inactive impregnatingsubst-anceand subsequent to the manufacture of the yarn subjecting thesame to a continuous high temperature to activate and diffuse theimpregnating substance through the yarn.

6. A process of impregnating fabrics containing undissolved powderedgilsonite disseminated through the fabric which consists in'passing thefabric by a continuous movement through a solvent bath and then througha heating chamber maintained at a temperature sufficiently high to causethe gilsonite to flow and diffuse throughout the fabric. m

7. A process of impregnating fabrics containing undissolved powderedgils'onite disseminated through the fabric which consists in passing thefabric by a continuous movement through a solvent bath such as carbontetrachloride and then through a heating chamber maintained at atemperature suiticiently high to cause the gilsonite to flow and diffusethroughout the fabric.

8. A process of impregnating fabrics manufactured from yarns whichcomprises mixing the impregnator with the stock prior to the making ofthe yarn, and subsequent to the manufacture of the fabric diffusing theimpregnator through the fabric.

9; A process of impregnating fabrics manufactured from strands whichconsists in incorporating an inactive impregnator into the strandsbefore the completion there of, manufacturing a woven fabric from thesaid strands and subsequent to the manufacture of the woven fabricactivating thesa-id impregnator to diffuse it through the fabric.

10. A process of impregnating fabrics manufactured from strands whichconsists in mixing an impregnator with the stock prior to the making ofthe strands, and subsequent to the manufacture of the fabric activatingthe said'impregnator to diffuse it through the fabric.

11. A process of impregnating fabrics manufactured from strands whichconsists in mixing a pulpy stock with an impregnator insoluble in waterprior to the manufacture of strands therefrom, manufacturing the yarnsinto a fabric and subsequently subjecting the woven fabric to the actionof a solvent and heat to diffuse the impregnator through the fabric.

In testimony whereof, I afiixmy signature.

JOHN ALLEN HEANY.

